Embossing press

ABSTRACT

A power press is provided with an assembly of relatively rotatable embossing rings and with a control system for rotating the rings and for reciprocating the press ram in timed relation to each other. The control system comprises a power driven rotary shaft; selectively engagable and disengagable drive transmitting connections between the shaft and the embossing rings, and an electrical circuit including switches which are closed and opened in predetermined sequence by rotation of the shaft, whereby the embossing rings are rotated step by step in predetermined order and the press ram is moved into and out of an embossing position during time intervals between successive steps of ring rotation.

United States Patent Alexander et al.

[ Aug. 26, 1975 [54] EMBOSSING PRESS 3,768,619 10/1973 Lewis 101/18 X [75] Inventors: Donald R. Alexander, Conway,

Car] w Johnson, Neenah, Primary Examiner-Clifford D. Crowder w Assistant Examiner-Edward M. Coven Attorney, Agent, or Firm lames E. Nilles {73] Assignee: Donald R. Alexander, Conway, Ark.

[22] Filed: Apr. 17, 1974 [57] ABSTRACT [21] Appl' 461346 A power press is provided with an assembly of relatively rotatable embossing rings and with a control sys- 52 US. Cl. 101/18; 101/109; 197/6.4 rem fer rotating the rings and for reciprocating the 51 im. c1. 1. B44B 5/00 press ram in timed relation to eaeh other. The control [58] Field of Search 197/6.4; 101/103, 3, 18-21, System Comprises a Power driven rotary Shaft; Seleco /gg 42 7g 109 tively engagable and disengagable drive transmitting connections between the shaft and the embossing 5 References Cited rings, and an electrical circuit including switches UNITED STATES PATENTS which are closed and opened in predetermined sey) quence by rotation of the shaft, whereby the emboss ing rings are rotated step by step in predetermined 2242505 5/1921 i 101/18 order and the press ram is moved into and out of an 2,652,772 9/1953 lm/72 embossing position during time intervals between suc- 2,968,237 l/196l 1on2 101/109 x eessive Steps of ring rotation- 3,269,510 8/1966 Peters 101/18 X 3,753,482 8/1973 Brown et =11. 101/18 x 4 Clam, 20 D'awmg Flgures i 1 I I I G 1* 1 1/3 2 i1 Z 1 fl 19 1 4 \a 1\ 18 n1 1\ 103 \1.\ 1

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PATENTED AUG 2 6 I975 SHEET 1S mmmmm hr D Y )0 \H \W J mew 3m mix mom Z Emm J m 02 M QJE m 0 J Em MY 1 i mmwm $36 20 13 QM m n h 6 r 1 id mww M N Qozfiom EMBOSSING PRESS BACKGROUND OF THE INVENTION The invention relates to power presses, and it is concerned more particularly with a power press for embossing multi-digit serial numbers successively in consecutive order upon a strip of sheet stock which is advanced step by step through the press.

Power presses of the above mentioned type have heretofore been developed and have been specifically adapted for the manufacture of automobile license plates. In such serial number embossing presses as heretofore developed an assembly of relatively rotatable embossing discs and a reciprocable embossing ram have been arranged in cooperative relation to each other, and provisions have been made for turning the embossing discs and for reciprocating the embossing ram sequentially in timed relation to each other. To that end, an indexing mechanism has been provided which was operable to turn the embossing discs step by step in predetermined order and which was operatively interrelated with the embossing ram in such a manner that a disc turning operation of the indexing mechanism was initiated by an upstroke of the ram from an embossing position, and so that a down stroke of the ram would bring it into an embossing position while the discs are held in indexed positions.

For mass production purposes, it is desirable to complete the embossing operations in extremely rapid succession, as for instance at the rate of 80 or more embossing operations per minute. However, such fast operation of an embossing press, and particularly of an embossing press for the manufacture of automobile license plates presents certain difficulties. In order to perform the embossing operation within a very short time, that is, in a second or less, the embossing stroke of the press ram will first of all have to be reduced to the required minimum which ordinarily will be less than V2 inch. Then, the indexing mechanism must be operable at a high speed and with utmost precision which again involves inertia problems and difficulties in timing the indexing mechanism and the short ram strokes relative to each other. Further, the ram pressures for embossing sheet metal such as is normally used for automobile license plates are considerably higher than those for ordinary punching process and t the various components of the embossing press and of the indexing mechanism must therefore be sturdily constructed and be able to stand up and function reliably under severe operating conditions and without undue wear.

U.S. Pat. application Ser. No. 296,602, filed on Oct. 11, 1972 by Donald R. Alexander for Serial Number Embossing Apparatus, now U.S. Pat. No. 3,824,921 issued July 23, 1974, discloses an embossing press for use in the manufacture of automobile license plates, and the embossing press disclosed in the present application involves features of improvement over the press disclosed in the mentioned earlier application.

SUMMARY OF THE INVENTION Generally, the present invention provides an improved power press which may be operated at relatively high speeds to emboss multi-digit serial numbers successively in consecutive order upon a strip of sheet stock which is advanced step by step through the press.

More specifically, the invention provides an embossing press of the mentioned character which incorporates an assembly of relatively rotatable embossing rings and an improved control system for rotating the embossing rings and reciprocating the press ram in times relation to each other.

The improved control system as contemplated by the invention incorporates a power driven indexing mechanism for the embossing rings, which is operatively interrelated with the operating mechanism for the embossing ram of the press in such a manner that an actuating signal for the press is emitted by operation of the indexing mechanism. In this respect the embossing press incorporating the present invention differs from the embossing press of the mentioned earlier application wherein an actuating signal for a power driven indexing mechanism is emitted by operation of the embossing ram.

The present invention further provides an improved serial number embossing press of the mentioned character wherein selectively engagable and disengagable clutch units are operatively interposed between an assembly of relatively rotatable embossing rings and an oscillating indexing arm, and wherein the clutch units are electrically controlled so as to rotate the embossing rings step by step in predetermined order by the oscillating indexing arm.

The invention further provides an improved serial number embossing press of the mentioned character wherein selectively engagable and disengagable lock units are operatively interposed between an assembly of relatively rotatable embossing rings and a stationary mounting structure for the rings, and wherein the lock units are electrically controlled so that the rings are positively secured against turning during the embossing operation, and so that the rings are selectively released for turning by the oscillating indexing arm.

The invention also provides an improved serial number embossing press incorporating an improved drive mechanism for an oscillating indexing arm whereby the indexing arm is steadily accelerated and decelerated without setting up objectionable inertia forces.

The improved embossing press provided by the pres ent invention also includes provisions for turning the decimal rings either step by step in predetermined order, or for turning any selected one of the decimal rings individually step by step independently ofthe others. Such provisions are of particular advantage for the production of automobile license plates where it may be desirable to terminate a production run short of the maximum available numbering range, and wherein a new production run is to be started with a serial number configuration other than that at which the previous production run was terminated.

THE DRAWINGS The foregoing and other features and advantages of the invention will become more fully apparent as this disclosure proceeds with reference to the accompanying drawings, wherein FIG. 1 is a perspective front view of an embossing press embodying the invention;

FIG. 2 is a perspective view similar to FIG. 1 but showing the press in a different condition of adjustment;

FIG. 3 is a side view of the press shown in FIG. 2;

FIG. 4 is a partial top view on line 4-4 of FIG. 3;

FIG. 5 is a view similar to FIG. 4 but showing parts in a different condition of adjustment;

FIG. 6 is an enlarged elevational view on line 6-6 of FIG. 4;

FIG. 7 is a top view similar to FIG. 4 but with parts omitted to expose structure hidden in FIG. 4;

FIG. 8 is an enlarged view of part of FIG. 7;

FIG. 9 is a section on line 9-9 of FIG. 8;

FIG. 10 is an enlarged elevational view partly in section on line 10-10 of FIG. 5;

FIG. 11 is a section on line 11-11 of FIG. 10;

FIG. 12 is an enlarged detail view, partly in section, on line 12-12 of FIG. 7;

FIG. 13 is a view, partly in section on line 13-13 of FIG. 12;

FIG. 14 is an elevational view on line 14-14 of FIG.

FIG. 15 is a top view of FIG. 14;

FIG. 16 is an elevational view, partly in section, on line 16-16 of FIG. 14;

FIG. 17 is a perspective diagram of a pneumatic circuit and associated parts for controlling the embossing press shown in FIGS. 1-16;

FIGS. 18 and 19 are operating diagrams corresponding, respectively, to FIGS. 4 and 5; and

FIG. 20 is a diagram of an electrical control circuit and associated parts for operating the embossing press shown in FIGS. 1-16.

DETAILED DESCRIPTION The basic component of the embossing press shown in FIG. 1 is a hydraulic press 1 of generally conventional construction, and more specifically of the type shown in U.S. Pat. No. 2,927,558 issued on Mar. 8, 1960 to R. Smilges for Hydraulic Press and Control Means. Briefly, the press 1 comprises a main frame 2 of the open gap or C type; a reciprocating ram 3, and a hydraulic power unit 4 (FIG. 19) within a hollow upper part of the frame 2. Also enclosed within the hol low upper part of the C frame 2 are an electric motor 6, a pump 7, and a belt drive 8 connecting the motor with the pump. The hydraulic power unit 4 includes an internal hydraulic circuit which is supplied with pressure fluid by the pump 7 and which is controlled by a solenoid valve 9. When the coil of the solenoid valve is energized, hydraulic pressure builds up within the power unit 4 and forces the ram 3 down on an embossing stroke, and when the solenoid coil is subsequently de-energized the ram 4 moves automatically from its lowered embossing position (FIG. 19) to a raised nonembossing position (FIG. 18).

The press frame 2 (FIG. 1) is provided at the bottom of its C'gap with an extension frame generally designated by the reference character 101. The extension frame 101 comprises a pair of side beams 11 and 12, a front cross beam 13, and a pair of front supporting legs 14 and 16. The rear ends of the side beams 11 and 12 are rigidly secured to opposite side portions of the press frame 2, and the front legs 14 and 16 sustain the beam assembly 11, 12 and 13 in a horizontal position. Slideably mounted on the side beams 11 and 12 of the extension frame 101 for horizontal back and forth movement relative to the press frame 2 is a subframe 102, and operatively mounted on the subframe 102 is a numerical registrating device comprising a concentric radial assembly of four decimal rings W, X, Y and Z, an oscillating indexing arm 103, and a drive mechanism for the indexing arm, generally designated by the reference character 104 (FIG. 6). A rack and pinion drive 105 (FIG. 3) is operable by a hand wheel 106 to shift the subframe 102 back and forth between the positions in which it is shown in FIGS. 1 and 2.

In FIG. 7, the subframe 102 is shown without the decimal rings to expose an anvil 107 and two radial support rails 108 and 109 which are secured in fixed positions on a platform 173 of the subframe 102 and on which the concentric decimal rings W, X, Y and Z are supported in rotatable relation to each other. Each of the decimal rings has a circular groove (FIG. 9) at its under side, and these grooves are engaged by guide rollers 111 on the anvil 107, and by corresponding guide rollers 112 and 113 on the support rails 108 and 109, respectively, to keep the rings centered on a common axis. Radial hold-down rollers 114 and 116 (FIG. 4) are suitably mounted on the subframe 102 in contact with the upper sides of the decimal rings to prevent upward separation of the rings W, X, Y, Z from the guide rollers 111, 112 and 113.

The indexing arm 103 (FIG. 10) has a hub sleeve 1 17 and a bracket end 118 extending radially outwardly from the sleeve 117 below the decimal rings W, X, Y, Z. Conical roller bearings 119 and 121 mount the arm 103 on a king pin 122 which is flanged to the subframe by cap screws 123 and extends axially of the rings W, X, Y, Z on the common axis of the latter.

The drive mechanism 104 for oscillating the indexing arm 103 about the axis of the king pin 122 is best shown in FIGS. 6, 7 and 17. It comprises an electric motor 124, a speed reduction unit 126 connected to the motor 124 and having a rotary output shaft 127; a

'counter shaft 128 mounted on the subframe 102 in bearings 129 and 131 (FIG. 6) for rotation on an axis extending parallel to and spaced radially from the axis of the king pin 122. A pulley 132 (FIG. 17) on the output shaft 127 of the speed reduction unit 126 is connected by a belt 133 with a sheave 134 which is keyed to the counter shaft 128. The transmission ratio between the motor 124 and the counter shaft 128 is so proportioned that the counter shaft 128 rotates in the direction of arrow 138 at a speed which is substantially lower than the armature speed of electric motor 124, a suitable speed for the counter shaft 128 being, for instance, RPM. A disc 137 (FIG. 17) is keyed to the shaft 128 for rotation therewith on substantially the same level as the bracket end 118 of the indexing arm 103. The disc 137 (FIG. 7) mounts an eccentric pin 138, and a connecting rod 139 is pivotally connected at one end to the pin 138 and at the other end to a wrist pin 141 (FIG. 6) on the indexing arm 103.

The radial spacing of the eccentric pin 138 (FIG. 7) from the axis of the counter shaft 128, and the radial spacing of the wrist pin 141 from the axis of the king pin 122 are so proportioned that a 360 turn of the disc 137 swings the indexing arm 103 in forward and rear ward directions about its pivot axis on the king pin 122 through angular range of 36.

FIGS. 4, 7, 17 and 18 show the dead center position of the connecting rod 139 which places the indexing arm 103 at one end of its 36 swinging range, and FIGS. 5 and 19 show the other dead center position of the connecting rod 139 which places the indexing arm 103 at the other end of its 36 swinging range.

A forward stroke of the indexing arm 103 from the FIG. 4 position to the FIG. 5 position will take place upon a 180 clockwise turn of the disc 137 from its FIG. 18 position to its FIG. 19 position; and a further 180 clockwise turn of the disc will subject the indexing arm 103 to a return stroke from its FIG. 5 position to its FIG. 4 position. The electric motor 124 drives the disc 137 at constant angular velocity, and during the first 180 clockwise turn of the disc 137, the indexing arm will be gradually accelerated from standstill to maximum angular velocity, and it will then be gradually decelerated to momentary standstill at the end of the forward stroke. During the next 180 clockwise turn of the disc 137 the indexing arm will again be gradually accelerated from standstill at the beginning of the return stroke to maximum angular velocity and during the second half of the return stroke, it will again be de celerated to standstill at the end of the return stroke.

In FIG. 18, the dash dotted line 142 designated the radial position to which the indexing arm 103 is swung by a 165 clockwise turn of the eccentric pin 138, and the dash-dotted line 143 designates the radial position to which the indexing arm is swung by a 180 clockwise turn of the eccentric pin 138. A short time interval is therefore provided during which the indexing arm remains almost at standstill at the end of its forward stroke while the counter shaft 128 continues to rotate at constant angular velocity. The same explanations apply to FIG. 19 where the dash dotted line 144 designates the radial position to which the indexing arm is swung by a 165 clockwise turn of the eccentric pin 138, and the dash dotted line 146 designates the radial position to which the indexing arm is swung by a 180 turn of the eccentric pin 138. Another short time inter val is therefore provided during which the indexing arm remains almost at standstill at the end of its return stroke while the counter shaft 128 continues to rotate at constant angular velocity.

AS will presently be explained in detail, driving connections between the indexing arm and the decimal rings, and locking connections between the decimal rings and the subframe are automatically established and interrupted during the short time intervals at which the indexing arm remains almost at standstill while the counter shaft continues to rotate at constant angular velocity. If, as mentioned previously, the counter shaft rotates at 80 RPM, only small fractions of a second will of course be available for the establishment and interruption of the mentioned driving and locking connections.

As shown in FIG. 10, a bank of four clutch units W1, X-1, Y-l and Z-l are mounted on the bracket end 118 of the indexing arm below the decimal rings W, X, Y, Z, respectively. The clutch unit X-l provides an engagable and disengagable torque transmitting connection between the indexing arm 103 and the decimal ring X by means of a reciprocable clutch pin 147 (FIG. 11) which is connected to the piston rod 148 of a pneumatic cylinder 149. Cap screws 151 secure the cylinder 149 to the underside of the end bracket 118, and hose lines 152 and 153 lead into the cylinder above and below the piston 154 therein. A guide bushing 156 (FIG. 11) for the clutch pin 147 is secured axially within the end bracket 118, and the upper end of the clutch pin 147 is tapered for axial entry into anyone of a circular series of equally spaced holes 157 in the decimal ring X.

The foregoing explanations of the clutch unit X-l analogously apply to the clutch units W1, Y-1 and Z-l, which comprise clutch pins 158, 159, I60, respectively (FIG. 7) and are operable by associated pneumatic cylinders each having a pair of hose lines 152 and 153. The decimal ring W (FIG. 10) has a circular series of 10 equally spaced clutch pin receiving holes 161; the decimal ring Y has a circular series of ten equally spaced clutch pin receiving holes 162; and the decimal ring Z has a circular series of 10 equally spaced clutch pin receiving holes 163, all of these clutch pin receiving holes being each lined with a bushing 164 as shown in FIG. 10.

During each return stroke of the indexing arm from its FIG. 5 position to the position which is indicated in FIG. 19 by the dash-dotted line 144, all of the clutch units W1, X-l, Y-1 and Z-l are kept in disengaged condition by air pressure admitted to their respective pneumatic cylinders through the upper hose lines 152 (FIG. 11), as will be explained more fully hereinbelow. At the same time all the decimal rings are secured against rotation from their indexed positions by means of four lock units W2, X-2, Y2, and Z-2 (FIG. 12) which are mounted on the subframe 102 in the space between the anvil block 107 (FIG. 7) and the ring support rail 109.

The lock units W2, X-2, Y2 and 2-2 are substantially duplicates of the clutch units W1, XI, Yl and Zl. The lock unit W2 provides an engagable and disengagable locking connection between the subframe 102 and the decimal ring W, and the lock units X2, Y-2 and Z-2 similarly provide engagable and disengagable locking connections between the subframe 102 and the decimal rings X, Y and Z, respectively. The lock unit W2 comprises a reciprocable locking bolt 158 (FIG. 13) which is connected to the piston rod 167 of a pneumatic cylinder 168. Cap screws 169 secure the cylinder 168 to a mounting block 171 which in turn is secured by cap screws 172 to a platform 173 ofthe subframe 102. Hose lines 152' and 153' lead into the cylinder 168 above and below a piston 176 therein. A guide bushing 177 (FIG. 13) for the lock bolt 158 is secured in the mounting block 171 and the upper end of the lock bolt 158' is tapered for axial entry into any one of the holes 161 of the decimal ring W.

The foregoing explanations of the lock unit W2 similarly apply to each of the lock units X-2, Y-2, 2-2. A lock bolt 147' (FIG. 12) of the lock unit X-2 is shiftable axially into and out of any of the clutch pin receiving holes 157 of the decimal ring X; a lock bolt 159' is shiftable axially into and out of any of the clutch pin receiving holes 162 of the decimal ring Y; and a lock bolt is shiftable axially into and out of any of the clutch pin receiving holes 163 of the decimal ring Z.

The mounting block 171 (FIG. 7) for the lock units W2, X-2, Y-2 and Z-2 is secured on the subframe 102 in such a position that the lock bolts 158', 147, 159' and 160 will register with overlying clutch pin receiving holes of the decimal rings W, X, Y, Z, respectively, whenever the indexing arm is in position at the end of a forward stroke (FIGS. 5 and 19).

FIG. 17 is a simplified diagrammatic showing of a pneumatic control system for the clutch units W1, Xl, Y-1, Z-l and for the lock units W2, X-2, Y-2 and Z-2. The indexing arm 103 is shown in FIG. 17 as in FIG. 18, in the starting position for a forward stroke; the clutch pins on the indexing arm are in retracted positions except the clutch pin 158 of the W-l unit which is in its projected ring W engaging position; and the lock bolts on the subframe are in their projected ring locking positions except the lock bolt 158' which is in its retracted ring W unlocking position. A bank of four solenoid valves W3, X-3, Y-3 and Z-3 are mounted in fixed positions on the subframe, each valve having two solenoid coils which may be alternately energized by an electrical control circuit as shown in FIG. 20 and which will be discussed more fully hereinbelow.

The solenoid valve W3 has an air inlet port, an air outlet, and a shiftable valve body, not shown, which in one position, when the solenoid coil 81A is energized, connects the inlet and outlet ports with conduit lines 181 and 182, respectively; and which in another position, when the solenoid coil SIB is energized, connects the inlet and outlet ports with the conduit lines 182 and 181, respectively. The same explanations apply to the solenoid valves X-3, Y-3 and Z-3. A manifold 183 connects a source of air pressure 184 with the inlet ports of the valves W3, X-3, Y-3 and Z-3.

The conduit line 181 of the valve W3 branches into the hose lines 152 and 153' of the clutch and lock units Wl and W2, respectively, and the conduit line 182 of the valve W3 branches into the hose lines 153 and 152 of the clutch and lock units W-l and W2, respectively. Accordingly, admission of air pressure to the conduit line 182, as shown in FIG. 17, projects the clutch pin 158 and simultaneously retracts the lock bolt I58; and admission of air pressure to the conduit line 181 would retract the clutch pin 158 and simultaneously project the lock bolt 158'. In other words, the clutch and lock units W-l and W2 are interconnected for seesaw operation, that is, when the clutch pin is up the lock bolt is down, and vice versa.

The foregoing explanations of the clutch unit Wl, the lock unit W2 and valve unit W3 are equally applicable to the X1, X2, X-3 units, and also to the Y-l, Y2, Y3 units, and to the Z-l, Z-2, and Z3 units. The clutch unit X-l and its associated lock unit X-2, as well as the clutch unit Y-l and its associated lock unit Y-2, and the clutch unit Z-l and its associated lock unit Z2 are operable seesaw fashion the same as the clutch unit WI and its associated lock unit W2.

As shown in FIGS. 4, 5 and 9, each of the decimal rings W, X, Y, Z is provided at its obverse side with a circular series of raised embossing digits to 9 at 36 circular spacings from each other. The embossing station of the registering device is designated in FIG. 4 by the radial line R, and in the condition of the device as shown in FIG. 4 the ciphers of all rings are radially aligned so that the digit configuration will be 0-000.

A change from the 0-000 digit configuration of FIG. 4 to the 0001 digit configuration of FIG. is effected as follows. In the FIG. 4 condition of the device, the W ring is coupled to the indexing arm by the projected clutch pin 158 (FIG. 17); the remaining clutch pins are retracted; and all rings are locked by the projected lock bolts except the ring W which is unlocked due to the retraction of lock bolt 158. A forward stroke of the indexing arm 103 from the FIG. 4 position to the FIG. 5 position will therefore turn the ring W one step and thereby bring its number 1 embossing digit into the embossing station.

During the last phase of the first forward stroke of the indexing arm, that is, while the arm moves from the line 142 position of FIG. 18 to the line 143 position, the solenoid coil SlA of the valve W-3 is is de-energized and at the same time, the coil SIB of the valve W3 is energized with the result that the driving connection between the indexing arm and the ring W will be inter rupted and the locking connection between the subframe and the ring W will be established.

The indexing arm will then start its return stroke from the FIG. 19 position and while it moves from the line 144 position of FIG. 19 to the line 146 position, the solenoid coil SIB of the valve W-3 will be de-energized and at the same time the coil 51A of the W3 valve will be re-energized. As a result, the driving connection between the indexing arm and the W ring will be reestablished and the locking connection between the W- ring and the subframe will be interrupted so that the indexing arm may move through another forward stroke and thereby bring the number 2 embossing digit of the W ring into the embossing station.

The described step by step advancement of the W- ring will automatically repeat itself in endless succession as long as the driving motor 124 is kept running. However, when the indexing arm 103 moves through the last phase of its ninth return stroke and its driving connection with the W ring will be re-established, the indexing arm will at the same time be coupled to the X ring so that the subsequent forward stroke of the indexing arm will advance not only the W ring but also the X ring one step, and the embossing digit combination will then be 0-010. Such simultaneous advance of the rings W and X by the tenth advance stroke of the indexing arm is obtained by the transmission of an energizing signal simultaneously to the solenoid coil SlA of the valve W3 and to the solenoid coil S2A of the valve X-3.

The energizing signal which causes the valve X-3 to couple the indexing arm 103 to the ring X at the end of the ninth return stroke of the indexing arm is produced by a counting switch 3LS (FIG. 14) which is mounted on the subframe 102 below the decimal ring W. The counting switch 3L5 has an actuating arm 186 (FIG. 16) which is spring biased to urge a roller 187 on the arm 186 against the underside of the ring W. A notch 188 at the underside of the ring W permits the switch 3L5 to close when the number 9 digit of the W ring moves into the embossing station. The switch 3LS opens when the cipher digit of the W ring moves into the embossing station and remains open during each successive step of the ring W until the number 9 digit of the ring W again moves into the embossing station. The second closure of the 3LS switch causes the ring X to advance one step bringing the number 2 digit of the ring X into the embossing station. Continuous step by step advancement of the ring W thus causes the ring X to advance one step after each full revolution of the ring W.

Additional counting switches 4LS and 5LS (FIG. 14) corresponding to the counting switch 3LS are mounted on the subframe 102 below the rings W and Y, respectively. The ring X has a notch like the notch 188 of the ring W, which causes the switch 4LS to close after each full revolution of the ring X; and the ring Y has a similar notch which causes the switch SLS to close after each full revolution of the ring Y. As will be explained more fully hereinbelow with reference to FIG. 20, switches 3LS, 4LS and 5LS are wired into the control circuit for the solenoid valves W3, X-3, Y-3 and Z-3 in such a manner that continuous rotation of the countershaft 128 will automatically advance the embossing digit configuration of the device step by step from 

1. An embossing press comprising a frame, a ram reciprocably mounted on said frame for back and forth movement between a nonembossing and an embossing position; an assembly of embossing rings mounted on said frame in cooperative relation to said ram and for relative rotation on a common axis; an indexing arm pivoted on said frame coaxially with said ring assembly; oscillating means for alternately effecting forward and reverse strokes of said indexing arm on its pivot axis; selectively engageable and disengageable torque transmitting means operatively interposed between said indexing arm and said embossing rings; and operatively interrelated control means for said torque transmitting means and for said ram responsive to said forward and reverse strokes of said indexing arm whereby said rings are rotated step by step in predetermined order upon successive fOrward strokes of said indexing arm and left in indexed positions during said reverse strokes of said indexing arm, and whereby said ram is held in said non-embossing position during said forward strokes of said indexing arm and reciprocated between said non-embossing and embossing positions during said reverse strokes of said indexing arm.
 2. An embossing press comprising a frame, a hydraulic power unit and an associated reciprocable embossing ram operatively mounted on said frame; solenoid operated valve means connected to said power unit for effecting back and forth movement of said ram between a non-embossing and an embossing position; an assembly of embossing rings mounted on said frame in cooperative relation to said ram and for relative rotation on a common axis, an indexing arm pivoted on said frame coaxially with said ring assembly; oscillating means for alternatively effecting forward and reverse strokes of said indexing arm on its pivot axis; alternately expandable and contractable cylinder units mounted on said indexing arm in engageable and disengageable relation, respectively, to said embossing rings; fluid conduit means and associated solenoid operated valve means connected with said cylinder units for selectively establishing and interrupting torque transmitting connections between said indexing arm and said embossing rings; and operatively interrelated electrical control means for said solenoid operated valve means of said cylinder units and for said solenoid operated valve means of said power unit responsive to said forward and reverse strokes of said indexing arm whereby said embossing rings are rotated step by step in predetermined order upon successive forward strokes of said indexing arm and left in indexed positions during said reverse strokes of said indexing arm, and whereby said ram is held in said non-embossing position during said forward strokes of said indexing arm and reciprocated between said non-embossing and embossing positions during said reverse strokes of said indexing arm.
 3. An embossing press as set forth in claim 2, wherein said oscillating means comprise a rotary drive shaft journalled on said frame and a connecting rod having eccentric pivot connections at its opposite ends, respectively with said drive shaft and with said indexing arm; and wherein said electrical control means comprise first and second electrical switches and actuating cams therefor rotatable in unison with said drive shaft for controlling said solenoid operated valve means of said cylinder units, and a third electrical switch and an actuating cam therefor rotatable in unison with said drive shaft for controlling said solenoid operated valve means of said power unit.
 4. An embossing press comprising a frame, a ram reciprocably mounted on said frame for back and forth movement between a non-embossing and an embossing position; an assembly of embossing rings mounted on said frame in cooperative relation to said ram and for relative rotation on a common axis; an indexing arm pivoted on said frame coaxially with said ring assembly; oscillating means for alternately effecting forward and reverse strokes of said indexing arm on its pivot axis; selectively engageable and disengageable torque transmitting means operatively interposed between said indexing arm and said embossing rings; selectively engageable and disengageable locking means operatively interposed between said frame and each of said embossing rings; and operatively interrelated control means for said torque transmitting means, for said locking means and for said ram responsive to said forward and reverse strokes of said indexing arm whereby all of said locking means are engaged and said ram is reciprocated between said non-embossing and embossing positions during said reverse strokes of said indexing arm, and whereby said locking means are selectively disengaged and said torque transmitting means are selectively engaged and operative to rotate said rings step by step in predetermined order upon successive fOrward strokes of said indexing arm while said ram is held in said non-embossing position. 